1// SPDX-License-Identifier: GPL-2.0
2/*
3 * system.c - a driver for reserving pnp system resources
4 *
5 * Some code is based on pnpbios_core.c
6 * Copyright 2002 Adam Belay <ambx1@neo.rr.com>
7 * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
8 * Bjorn Helgaas <bjorn.helgaas@hp.com>
9 */
10
11#include <linux/pnp.h>
12#include <linux/device.h>
13#include <linux/init.h>
14#include <linux/slab.h>
15#include <linux/kernel.h>
16#include <linux/ioport.h>
17
18static const struct pnp_device_id pnp_dev_table[] = {
19 /* General ID for reserving resources */
20 {"PNP0c02", 0},
21 /* memory controller */
22 {.id: "PNP0c01", .driver_data: 0},
23 {.id: "", .driver_data: 0}
24};
25
26static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
27{
28 char *regionid;
29 const char *pnpid = dev_name(dev: &dev->dev);
30 resource_size_t start = r->start, end = r->end;
31 struct resource *res;
32
33 regionid = kmalloc(16, GFP_KERNEL);
34 if (!regionid)
35 return;
36
37 snprintf(buf: regionid, size: 16, fmt: "pnp %s", pnpid);
38 if (port)
39 res = request_region(start, end - start + 1, regionid);
40 else
41 res = request_mem_region(start, end - start + 1, regionid);
42 if (res)
43 res->flags &= ~IORESOURCE_BUSY;
44 else
45 kfree(objp: regionid);
46
47 /*
48 * Failures at this point are usually harmless. pci quirks for
49 * example do reserve stuff they know about too, so we may well
50 * have double reservations.
51 */
52 dev_info(&dev->dev, "%pR %s reserved\n", r,
53 res ? "has been" : "could not be");
54}
55
56static void reserve_resources_of_dev(struct pnp_dev *dev)
57{
58 struct resource *res;
59 int i;
60
61 for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_IO, num: i)); i++) {
62 if (res->flags & IORESOURCE_DISABLED)
63 continue;
64 if (res->start == 0)
65 continue; /* disabled */
66 if (res->start < 0x100)
67 /*
68 * Below 0x100 is only standard PC hardware
69 * (pics, kbd, timer, dma, ...)
70 * We should not get resource conflicts there,
71 * and the kernel reserves these anyway
72 * (see arch/i386/kernel/setup.c).
73 * So, do nothing
74 */
75 continue;
76 if (res->end < res->start)
77 continue; /* invalid */
78
79 reserve_range(dev, r: res, port: 1);
80 }
81
82 for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_MEM, num: i)); i++) {
83 if (res->flags & IORESOURCE_DISABLED)
84 continue;
85
86 reserve_range(dev, r: res, port: 0);
87 }
88}
89
90static int system_pnp_probe(struct pnp_dev *dev,
91 const struct pnp_device_id *dev_id)
92{
93 reserve_resources_of_dev(dev);
94 return 0;
95}
96
97static struct pnp_driver system_pnp_driver = {
98 .name = "system",
99 .id_table = pnp_dev_table,
100 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
101 .probe = system_pnp_probe,
102};
103
104static int __init pnp_system_init(void)
105{
106 return pnp_register_driver(drv: &system_pnp_driver);
107}
108
109/*
110 * Reserve motherboard resources after PCI claim BARs,
111 * but before PCI assign resources for uninitialized PCI devices
112 */
113fs_initcall(pnp_system_init);
114